首先欢迎来到 Xamarin 世界.

First off welcome to the Xamarin world.

其次，您拥有的模板是正确的.它们只是在 Visual Studio 2017 中进行了一些更改.例如，如果您想创建一个 PCL(可移植类库)项目，则选择跨平台应用程序并单击确定.比你得到以下屏幕:

Secondly your templates that you have are correct. They simply changed up a bit in visual studio 2017. For instance, if you want to create a PCL ( Portable Class Library ) project, you select cross-platform app and click ok. Than you get following screen:

这里可以选择你的编码策略(我在截图中选择了PCL).

Here can select your coding strategy ( I chose PCL in screenshot ).

如果有更多问题，请不要犹豫，祝你好运；)

If more questions don't hesistate to ask and goodluck ;)